Magnetic field-assisted solvothermal synthesis and the magnetic properties of Fe-doped CeO2 nanoparticles

Fe-doped CeO2 powders were prepared by the magnetic field-assisted solvothernal synthesis method. These powders were characterized using X-ray diffraction (XRD), scan electron microscopy (SEM), transmission electron microscopy (TEM) and magnetization measurement as a function of the field. The results showed that in the nanoparticles prepared without a magnetic field, increasing the Fe doping concentration caused morphological evolution. In pure CeO2, the morphology showed a hollow sphere-like structure. In doped CeO2 with 5 wt% Fe, the morphology showed a loose sphere-like structure which was self-assembled by many small, round, sheet-like grains. In doped CeO2 with 30 wt% Fe, the morphology showed a cross flower-like structure composed of many plate-like grains. When a magnetic field of 0.8 T was introduced, the sphere-like structure became more looser at a 5 wt% Fe concentration and a larger number of nanowires were formed. At a 30 wt% Fe concentration, cluster flower-like grains composed of many regular plate-like grains were observed. Additionally, the Fe-doped CeO2 nanoparticles showed weak ferromagnetism behavior at room temperature. Increasing the Fe doping concentration improved the ferromagnetism of nanoparticles. At a 30 wt% Fe doping concentration, applying a magnetic field of 0.8 T promoted the improvement of ferromagnetism.